March 27, 2012

Cranial variation and the transition to agriculture in Europe

Students of physical anthropology won't be surprised that Pinhasi and von Cramon-Taubadel find that the Neolithic and pre-Neolithic populations in Europe were differentiated cranially as they were apparently genetically.

It has long been recognized that the ancient European population was different than the Upper Paleolithic population of the continent. Carleton Coon ascribed this differentiation to migration of narrow-faced Mediterraneans into the territory of the robust broad-faced Upper Paleolithics. Ilse Schwidetzky also viewed migration from the Southeast of gracile Mediterraneans who gradually replaced broad-faced Cro-Magnoids.

So, it is nice to read that the re-analysis of a wide assortment of skulls on 15 cranial variables has revealed that:

The major shape differences separating hunter-gatherer Mesolithic populations and farming Neolithic populations are coded by PC1 with Neolithic specimens having longer and taller vaults, and Mesolithic specimens having larger, and broader faces.

There are two (or three) puzzles in European prehistory:

How the robust, low-skulled, broad-faced hunter-gatherers became more high-skulled, narrow-faced and gracile

How the latter became brachycephalized until early modern times

Why they have become partially debrachycephalized in the most recent of times

Anthropologists have tended to favor either migration or adaptation to explain these trends, with some even suggesting simple phenotypic plasticity without any major genetic change. It is now clear that -whatever the role of adaptation or plasticity- the Upper Paleolithic population of Europe did notsimply change to become more gracile on its own, but was affected by an already gracile population of foreign origin who set the ball rolling. There is already work on the genetic basis of facial structure, so, it is quite possible that eventually we'll be able to track directly the genetic changes underlying the phenotypic transformation of Europeans.

From the paper:

Nonetheless, the craniometric analysis allows us to discern certain patterns. For example, the ‘Forest Neolithic’ specimens are clearly much more similar to other Mesolithic hunter-gatherers than to Neolithic farmers in terms of their craniometric shape, suggesting a large degree of cultural diffusion in this region. However, it is also evident that the earliest potential colonisers of southeast and central Europe are very similar to the Anatolian Çatal Höyük population, congruent with an initial demic diffusion from the Near East/Anatolia.

The "Forest Neolithic" included pottery-using groups of eastern Europe (hence Neolithic, since pottery is one of the hallmarks of that period), but should not be confused with the early agriculturalists who apparently practiced farming without pottery early on in the Near East and Greece, and then acquired pottery and expanded with it into the rest of Europe, together with their full "package" of domesticated crops and animals.

Human Biology vol. 84

Cranial variation and the transition to agriculture in Europe

Ron Pinhasi, Noreen Von Cramon-Taubadel

Abstract

Debates surrounding the nature of the Neolithic demographic transition in Europe have historically centred on two opposing models; a 'demic' diffusion model whereby incoming farmers from the Near East and Anatolia effectively replaced or completely assimilated indigenous Mesolithic foraging communities and an 'indigenist' model resting on the assumption that ideas relating to agriculture and animal domestication diffused from the Near East, but with little or no gene flow. The extreme versions of these dichotomous models have been heavily contested primarily on the basis of archaeological and modern genetic data. However, in recent years there has been a growing acceptance of the likelihood that both processes were ongoing throughout the Neolithic transition and that a more complex, regional approach is required to fully understand the change from a foraging to a primarily agricultural mode of subsistence in Europe. Craniometric data have been particularly useful for testing these more complex scenarios, as they can reliably be employed as a proxy for the genetic relationships amongst Mesolithic and Neolithic populations. In contrast, modern genetic data assume that modern European populations accurately reflect the genetic structure of Europe at the time of the Neolithic transition, while ancient DNA data are still not geographically or temporally detailed enough to test continent-wide processes. Here, with particular emphasis on the role of craniometric analyses, we review the current state of knowledge regarding the cultural and biological nature of the Neolithic transition in Europe.

I've been saying this since 2005. I hope, now Maju, since that both physical anthropology and genetics, you will be able to slowly emerge out of your sentiments for Paleolithic continuity of Basques. Your people look don't look Mesolithic European nor do your people harbor their genes. You are an Anatolian, and Dienekes is your brother.

"With the increasingly large body of evidence that diet shapes cranial features, it is sad to see that this aspect - while important and perhaps dominant - is largely ignored in many studies."

OK. so, if its like this, there must be evidence.

Where are one egg twins who grew up in 2 different families, who had different kind of diet and one is broad faced and short skulled while his genetical idential twin is slimfaced and long skulled.

And what change in dient caused Europeans to change from broadfaced, shortskulled in hunter gatherer age, to slimfaced and longskulled in farming age and back to broadfaced and shortskulled in the industrial age.

And why is this a world wide effect? The Chinese skulls decrease in lengh since 3K years aswell.

Where are one egg twins who grew up in 2 different families, who had different kind of diet ...

...And why is this a world wide effect?

Fanty,

The past, extreme changes in diet simply don't occur in the modern world. However, diet has changed world-wide, so it is a good explanation for at least some cranial changes.

HGs have a diet high in tough fiber, and tend to use all of their meat resources - which means a lot of gnawing off and biting into bones.

With ceramic and later metallic vessels, long-duration cooking became much more practical and prevalent, changing the food to one for which the jaws are hardly challenged, and thus leading to much smaller jaws and over-crowding of teeth. But the reduced stress also affects other parts of the scull where muscles are attached.

There are likely additional factors such as more sophisticated tools that require less usage of teeth, sleeping on softer beds and with pillows, different practices of carrying and binding infants during field work (or reduced need to do so), and many more that are all more plausible than some weird world-wide co-evolution within the time span of a few thousand years.

Anders Götherström, whose work was previously cited here, has an article out this week in Science. Differences between Swedish Neolithic farmers and hunters show the farmers have closets relationship to today's population of Sardinia, Cyprus and Italian Tuscany.

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